Study design: A double-blind parallel controlled trial Setting: outpatient clinic Inclusion criteria: Subjects between 40 and 75 years of age referred by a physician to the Pulmonary Rehabilitation Program, with a clinical and spirometric diagnosis of moderate to severe COPD according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD).
Outcome measurements: Inspiratory muscle strength (using maximal inspiratory pressure, MIP), exercise capacity (using six-minute walk test) and dyspnea were measured.
